Fabrication of nanostructured NiO and NiO:Cu thin films for high-performance ultraviolet photodetector

Abstract

In this work, pure NiO and NiO:Cu based photodetectors with different concentrations of Cu dopants (0, 0.5,1.0, and 1.5 wt%) were coated on glass substrates by using a simple, low cost nebulizer spray pyrolysis technique. Their structural, morphological, optical (UV–Vis absorption and photoluminescence), and ultraviolet (UV) sensing features were characterized with state-of-the-art analytical techniques. The structural studies confirm that the prepared films have crystalline nature and possess a cubic structure. From the absorption measurement, the optical bandgap ( E g ) of the deposited films decreases with the increase in Cu dopants. Photoluminescence study illustrates that 1.0% of Cu doping significantly improves the physical property of the NiO:Cu films and also its UV sensing study suggests that the 1.0% of NiO:Cu film could be better suited for high-speed optoelectronic devices due to their high Responsivity (0.202 AW -1 ), External quantum efficiency (47%), and Detectivity (5.9 × 10 9 jones) values. A possible mechanism of the photodetector performance under air and UV illumination is also discussed in this work. • First time investigation on Cu insists of NiO films based UV photodetector by simple nebulizer spray method. • Reported the increase of photocurrent with respect to bias voltage for enhancing photoelectric properties. • Decrease of the optical bandgap for Cu doped films due to the observed redshift in absorption and higher crystallite size. • Maximum responsivity, external quantum efficiency, and specific detectivity were observed for the 1% Cu doped NiO detector. • A possible mechanism for enhancing photocurrent under UV illumination was also discussed with a schematic diagram.